Maltose dependent degrons, maltose-responsive promoters, stabilization constructs, and their use in production of non-catabolic compounds

A method for producing a heterologous non-catabolic compound, the method comprising:

• (a) culturing a population of a genetically modified host cell in a culture medium comprising an essential compound and a carbon source comprising a maltose based inducer, wherein the genetically modified host cell comprises:
• (i) a heterologous nucleic acid for producing the heterologous non-catabolic compound, wherein the heterologous nucleic acid is operably linked to a first Gal4p-responsive promoter;
• (ii) a heterologous nucleic acid encoding a conditional essential gene product of a biosynthetic pathway for producing an essential compound, wherein the heterologous nucleic acid is operably linked to a second Gal4p-responsive promoter;
• (iii) a nucleic acid encoding Gal4p;
• (iv) a heterologous nucleic acid encoding Gal80p fused in frame to a maltose dependent degron, operably linked to a maltose-responsive promoter,
• wherein the maltose based inducer in the culture medium limits the amount of the non-catabolic compound produced by the genetically modified host cell, and wherein an amount of the essential compound produced by the genetically modified host cell is limited;
• and
• (b) culturing the population or subpopulation thereof in a culture medium comprising no added essential compound or a sufficiently low amount of the added essential compound and the carbon source wherein the maltose based inducer is absent or in sufficiently low amounts such that the activity of the maltose-responsive promoter is limited, which, in turn, increases production of the heterologous non-catabolic compound compared to step (a).